All wine eventually spoils and turns into vinegar. Volatile acidity (VA) essentially refers to where a given wine sits on that spectrum of freshness. The more acetic acid and ethyl acetate that’ve built up in a wine, the more likely you’ll be to dump it down the drain. Excessive VA in a previously unopened bottle is typically a sign of oxygen exposure during winemaking, low-quality grapes, or less-than-immaculate conditions in the winery.Low amounts of VA can be viewed as a neutral, or even positive trait, contributing tart flavors like raspberry and passion fruit. At higher levels, VA causes wine to smell like kombucha, nail polish remover, and vinegar. While sulfur is effective in preventing VA, that tends to be a non-starter for most natural winemakers. As a result, VA can be more common in natural wines.